1. Field of the Invention
The present invention relates to an electronic camera that inserts a visible specific image (a so-called digital watermark) indicating a copyright or the like into a captured image in such a manner that the original image can be restored later.
The present invention also relates to an image processing method adopted to restore an original image by removing a specific image from an image file created in an electronic camera or the like.
2. Description of the Related Art
There are digital watermarking technologies known in the related art whereby a digital watermark is embedded in image data. For instance, Japanese Laid Open Patent Publication No. 2000-358154 discloses a method of embedding a visible digital watermark in image data by altering the color of a portion of the image data within a specific range.
In addition, Japanese Laid Open Patent Publication No. 2000-151411 discloses a method whereby a digital watermark is attached after first decoding compressed data resulting from image compression and then the image is compressed again.
When major sporting events, such as the Olympic Games, take place, great volumes of image data of images photographed by a plurality of contract photographers are gathered at a newspaper publisher or the like. Under such circumstances, it is desirable that the newspaper publisher handling such large volumes of image data be able to distinguish at-a-glance a specific photographer, a specific event or the like quickly, simply by looking at each set of image data.
In addition, the photographer will be able to subsequently claim copyright with great ease to image data he is dispatching if the image data are distributed in a state that will enable at-a-glance identification of the photographer.
Accordingly, the inventor of the present invention conceived that such needs might be satisfied by attaching visible information indicating a copyright or the like to image data in an electronic camera.
However, it will be difficult to attach information indicating copyright or the like in a legible state by adopting the method disclosed in Japanese Laid Open Patent Publication No. 2000-358154, in which the color within a specific image plane range of the image data is altered. In addition, the method disclosed in Japanese Laid Open Patent Publication No. 2000-151411 requires compressed data to be first decoded before attaching a digital watermark and then the data to undergo image compression again. For this reason, the onus of the processing executed in the electronic camera is heavy, leading to problems such as a lower photographing speed per frame.